Spatial Analysis and Heatmap Visualization of Groundwater Arsenic Contamination in Dhaka and Mymensingh Divisions, Bangladesh

Zerin Tasnim, Md. Main Uddin Miah, Quamrun Nahar, Shamima Nasrin, Fariha Islam

Arsenic contamination in groundwater poses a critical public health threat in Bangladesh, particularly in its central and northern regions. This study investigates the spatial distribution of arsenic concentrations across the Dhaka and Mymensingh divisions using geospatial clustering and interpolation techniques. A total of 1,124 groundwater samples were analyzed using Python-based spatial clustering and Inverse Distance Weighting (IDW) interpolation in QGIS to generate contamination heatmaps. Results reveal significant hotspots in Manikganj, Faridpur, Narsingdi, and Tangail, where arsenic levels frequently exceed the national limit of 50 μg/L and the WHO guideline of 10 μg/L. Safer zones were observed in districts such as Sunamganj, Chandpur, and Rajbari. This spatial understanding supports targeted mitigation and informed groundwater management policies.